Work supporting attachment for hoists



March 14, 1950 w. s. HoovER ETAL 2,500,459

WORK SUPPORTING ATTACHMENT FOR HOISTS Filed May 24, 1948 I n n- Wf/ amgVL//f/fl Siwa/IMO@ i 717i!! iam 5. l'oo z/er' and Thamaslfjea www mentesMu. 14, 195o :rows

UNITED s'rA'rEs PATENT orrics l y y zsoosso wuuamaneemmsnewnnee,

, ,Callf sspueeuen my :4, im. semi Na zam Chilli. 287-1) This inventionrelates to an auxiliary lowering attachment for hoists and has as itsprimary object the provision of a device for use in connection with ahoist, such as ablock and tackle, employed in the assemblage of heavystructures, in cases where it is necessary to bring a suspended partinto accurate alignment or assemblage with a stationary part to which itis to be united, and whereby the suspended part may be loweredindependent of the hoist from a position slightly above the position itis to occupy when assembled, and whereby proper positioning of thesuspended piece may be more readily eifected than through Athe medium ofthe hoist alone.

Another object is to provide a lowering device by means of which a loadmay be lowered with extreme slowness whereby the load may be set down orpositioned on a determined plane with a high degree of accuracy as indisposing a suspended heavy structure in apposition in which sideopenings or projections thereon are brought into register or alignmentwith side openings or projections on another structure. v

vAnother object is to provide an auxiliary lowering attachment forhoists which is hydraulically controlled and in which the loweringoperation' is effected through the manipulation of -a' control valve topermit discharge of entrapped fluid beneath a load supporting piston to.allow the latter to move downwardly in accordance with the volume ofthe released iluid.

Another object is to provide a construction whereby the load carryingpiston maybe auto'- matically restored to normal on being relieved ofits load -but under the-control of a hydraulic control valve.

A further object is to provide an arrangement whereby a load carryingpiston in moving under the iniiuence of the load imposedv thereon willmove in opposition tb the resistance of hydraulic fluid passing througha restricted oriilce and also against the increasing resistance 4oi? acoiled" spring tensioned to oppose movement of the piston under itsload.

With the foregoing objects in view, together with such other objects andadvantages as may subsequently appear, the'invention resides in theparts and in the combination, construction and arrangement of partshereinafter described and claimed, and illustrated by way of example in'the accompanying drawing, in which:

Fig. l is a view of the attachment as seen in vertical section withparts shown in elevation;

Fig. 2 is a detail horizontal section taken on the line2-2ofF1g.1: and

, 2 Flg.3isadiagraminsideelevationillusnating the application and modeof operation of the invention. Referring to.the drawings morespecifically A lindicates an elongated tubular housing formed with anend wall I constituting a lower when v`the housing is disposed in anupright or. vertical' position. The interior of the housing A V isformed with a cylindrical interior which is' preferably lined with areplaceable cylinder I whicl'rsnugly fits the inner surface of thehousing and extends'rrom the lower' end wall I to. the other or vupperend of the housing, which latter' is provided with a removable cap Iclosing the upper end of the cylinder I. The cap I is de tachab'lysecured tothe upper end of the housingAas by bolts 1. lThe cap Iisiltte'd with'i.' yoke Ifor engagement with .the hook I of theconventional' block and tackle B as illustrated in 3, or other suitablehoist, whereby the. husin'gjl may be suspended in its vertical posiion.;I

Arranged within the 'cyunde'i is a piston c fixed n: a stem II'projecting through the lower end wall I of the housing and fitted onits. lower end with a swivel ,hookg il for engagement with piece l? tobe and lowered in relationto" a nx plece E. A packing gland!! iscarried?- by thu' end wall I and encompassesthezlte'lrllfy 'I l toiriford @seal therearound. A coiled spinarl'A between the piston C andwall Ijbf the housing and is tensioned tolyield# and also to restore theptstoi to its'uppennsat position when freed of a load after depressed.

Formed in the iower'feu-pertion of inder I is ayport- Il which "openstoa ls in the' housing s leading to the' mtenervoff the eyunder abovethe piston c adjacent the *up-f per end of, the cylinder through a portII. The

cylinder e and the passage is is nneswitna ametrically through thestemadaptedtobe siiioned in and out oi' communication with the passage I5.The stem I1 is encompassed by a packing gland I9 and is tted with ahandle 20 by which it may be turned to open or close the valve B.

A collar 2| is fixed on the stem i0 in suitable spaced relation to thewall l to serve as a Stop to limit downward movement of the piston; thecollar being adapted to abut the end wall I when the stem I is advancedtherethrough the determined distance.

In the application and operation of the invention the housing A issuspended from the hoist B with the piston C in its uppermost positionin the cylinder and with the valve H closed. The piece D to be suspendedis attached to the hook l i and the hoist B is operated to elevate thepiece to a plane slightly above the position that the piece D is tooccupy when assembled with its companion piece E as shown in full linesin Fig. 3. Having thus disposed the piece D proximate its assembledposition the valve H is operated to partially open the passage l5thereby permitting the ow of lluid G from beneath the piston C under theload imposed thereon, thus permitting the piston to move downwardly inopposition to the spring F. The piece D is thus lowered to the desiredpoint whereupon the valve H is closed, thereby cutting oil the ow of theuid G from beneath the piston C and preventing further downward movementof the latter within the cylinder. The piece D will then be heldsuspended in its secondary lowered position, as illustrated by dottedlines in Fig. 3 with projections a on the piece D aligned with holes bin the piece E so that the projections may then be readily inserted inthe holes. If perchance the piece D is thus lowered beyond the point ofor below the plane of its assemblage with the piece E it may again beelevated by the hoist B and if need be the valve H again manipulated toeffect the lowering of the piece to the required position.

During the downward movement of the piston C under the load of the pieceD the spring F is placed under compression so as to resist downwardmovement of the piston and which resistance increases progressively asthe piston moves downwardly. The spring F thus yieldably opposesdownward movement of the piston C which with the control ail'orded bythe valve H enables extremely delicate regulation of the lowering of thepiece D relative to the hoist B.

While we have shown and described a specific embodiment of our inventionwe do not limit ourselves to the exact details of construction setforth, and the invention embraces such changes, modifications andequivalents of the parts and their formation 4and arrangement as comewithin the purview of the appended claims.

We claim:

1. In a supplemental lowering attachment for hoists, a housing, anenclosed cylinder within said housing, a piston in said cylinder. a stemattached to said piston having an end portion extending exteriorly o!said housing, a load engaging member on said stem, a hydraulic uidwithin said housing nlllng said cylinder on opposite sides of saidpiston, a passage connecting the opposed end portions of said cylinder,a regulating valve in said passage, and a coiled spring wound aroundsaid stem in said cylinder yieldably opposing movement of said piston inone direction under the urge of a load on said stem and operable torestore the piston from an advanced to a normal position when the stemis free oi.' a load and when the valve is open.

2. In a supplemental lowering attachment for hoists, a tubular housing,an end wall on said housing, a cylinder lining the interior of saidhousing having a port adjacent each of its ends, said housing beingformed with a passage leading between said ports, a removable cap onsaid housing closing one end of said cylinder, a piston' within saidcylinder, a stem extending through said end wall on which said piston ismounted, a coiled spring interposed between said piston and end wallyleldably opposing movement of said piston in one direction and operableto move the piston in the opposite direction, a hydraulic fluidoccupying the space Within said cylinder on opposite sides of saidpiston and lling said ports and passage, and a control valve in saidhousing arranged to close said passage and cut oil flow of fluidtherethrough and operable to open said passage to the oW of the uidtherethrough.

3. The structure called for in claim 2 together with a collar on thestem cooperable with the end wall to limit movement of said stem in onedirection.

4. In a supplemental lowering attachment for hoists, a cylinder, apiston therein, a stem carrying said piston, a housing encompassing saidcylinder having an end wall through which said stem projects, saidcylinder having a port adjacent each end thereof and said housing havinga passage connecting said ports, a hydraulic uid filling said cylinderon opposite sides of said piston and occupying said ports and passage, acontrol valve for regulating the flow of uid through said passage andfor preventing such flow, means for attaching said housing to a hoist ina suspended position, and means for suspending a load on said stem.

5. The structure called for in claim 4 togetherv with spring means foryleldably opposing advance movement of said stem in one direction underthe inuence of a load imposed thereon and operable to move the stem inthe other direction after having been advanced on being relieved of aload.

- WILLIAM S. HOOVER.

THOMAS H. REA.

No references cited.

